This project will evaluate the myocardial behavior of a new class of fatty acid analogs labeled with 11C, l8F and 123I. The nature of these fatty acids is based on the inhibition of the Beta-oxidation process. The agents to be developed are designed to enter the cell as fat but should not be capable of undergoing complete metabolism. The study will define the relationship of the fatty acid analog structure to its ,myocardial kinetics, measure the extraction fraction of the radiopharmaceutical in the basal state and relate the behavior of these materials to regional myocardial blood flow. These studies should define the potential of these radiopharmaceuticals for evaluating the myocardium and lay the ground work for subsequent studies in man.